Neovascularized implantable cell homing encapsulation platform with tunable local immunosuppressant delivery for allogeneic cell transplantation.

Cell encapsulation is an attractive transplantation strategy to treat endocrine disorders. Transplanted cells offer a dynamic and stimulus-responsive system that secretes therapeutics based on patient need. Despite significant advancements, a challenge in allogeneic cell encapsulation is maintaining sufficient oxygen and nutrient exchange, while providing protection from the host immune system. To this end, we developed a subcutaneously implantable dual-reservoir encapsulation system integrating in situ prevascularization and local immunosuppressant delivery, termed NICHE. NICHE structure is 3D-printed in biocompatible polyamide 2200 and comprises of independent cell and drug reservoirs separated by a nanoporous membrane for sustained local release of immunosuppressant. Here we present the development and characterization of NICHE, as well as efficacy validation for allogeneic cell transplantation in an immunocompetent rat model. We established biocompatibility and mechanical stability of NICHE. Further, NICHE vascularization was achieved with the aid of mesenchymal stem cells. Our study demonstrated sustained local elution of immunosuppressant (CTLA4Ig) into the cell reservoir protected transcutaneously-transplanted allogeneic Leydig cells from host immune destruction during a 31-day study, and reduced systemic drug exposure by 12-fold. In summary, NICHE is the first encapsulation platform achieving both in situ vascularization and immunosuppressant delivery, presenting a viable strategy for allogeneic cell transplantation

Glucose-Functionalized, Serum-Stable Polymeric Micelles from the Combination of Anionic and RAFT Polymerizations

Poly­(ethylene-<i>alt</i>-propylene)–poly­[(<i>N</i>,<i>N</i>-dimethylacrylamide)-<i>grad</i>-(2-methacrylamido glucopyranose)] (PEP–poly­(DMA-<i>grad</i>-MAG), or PG) diblock terpolymers were synthesized by combining anionic and reversible addition–fragmentation chain transfer (RAFT) polymerizations. An ω-trithiocarbonate-functionalized PEP homopolymer served as the macromolecular chain transfer agent (macroCTA), and RAFT copolymerizations of DMA and a trimethylsilyl-protected MAG (TMS-MAG) monomer gave a family of PG diblock terpolymers after hydrolysis. The terpolymers had similar degrees of polymerization, and the MAG content ranged from 3.5 to 39 mol % in the hydrophilic block. At 70 °C, the reactivity ratios of DMA (1) and TMS-MAG (2) were determined to be <i>r</i>₁ = 1.86 ± 0.07 and <i>r</i>₂ = 0.16 ± 0.01, and thus the poly­(meth)­acrylamide blocks in the PG diblock terpolymers were likely to be gradient copolymers. Micellar dispersions from PG diblock polymers in water were examined by cryogenic transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS). Spherical micelles with core radii of ca. 7 nm and overall hydrodynamic radii of ca. 15 nm were the predominant morphologies observed in all samples prepared by sequential nanoprecipitation and dialysis. The electron-dense MAG moieties greatly increased the native contrast of the micellar coronae, which were clearly viewed as gray halos around the micellar cores in samples with relatively large MAG content. The stability of the glucose-installed micelles was tested in four biologically relevant media, from simple phosphate-buffered saline (PBS) to fetal bovine serum (FBS), using a combination of DLS and cryo-TEM measurements. Micellar dispersions from a PG diblock terpolymer with 16 mol % of MAG of the hydrophilic block were stable in 100% FBS over at least 14 h, suggesting their minimal interactions with serum proteins. Control experiments suggested that micelles composed of PDMA alone in the corona had similar serum stabilities. These sugar-functionalized micelles hold promise as <i>in vivo</i> drug delivery vehicles to possibly prolong circulation time after intravenous administration

Viral load Reduction in SHIV-Positive Nonhuman Primates via Long-Acting Subcutaneous Tenofovir Alafenamide Fumarate Release from a Nanofluidic Implant

HIV-1 is a chronic disease managed by strictly adhering to daily antiretroviral therapy (ART). However, not all people living with HIV-1 have access to ART, and those with access may not adhere to treatment regimens increasing viral load and disease progression. Here, a subcutaneous nanofluidic implant was used as a long-acting (LA) drug delivery platform to address these issues. The device was loaded with tenofovir alafenamide (TAF) and implanted in treatment-na&iuml;ve simian HIV (SHIV)-positive nonhuman primates (NHP) for a month. We monitored intracellular tenofovir-diphosphate (TFV-DP) concentration in the target cells, peripheral blood mononuclear cells (PBMC). The concentrations of TFV-DP were maintained at a median of 391.0 fmol/106 cells (IQR, 243.0 to 509.0 fmol/106 cells) for the duration of the study. Further, we achieved drug penetration into lymphatic tissues, known for persistent HIV-1 replication. Moreover, we observed a first-phase viral load decay of &minus;1.14 &plusmn; 0.81 log10 copies/mL (95% CI, &minus;0.30 to &minus;2.23 log10 copies/mL), similar to &minus;1.08 log10 copies/mL decay observed in humans. Thus, LA TAF delivered from our nanofluidic implant had similar effects as oral TAF dosing with a lower dose, with potential as a platform for LA ART